Hello i searched and searched and searched my self about a year ago for exactly what you are asking about. I probaully spent about 2 months searching online for different tank for ball pythons my self when i was first interested in getting them after a freind of mine introduced me to the species. tottal open top or tottal screen tops are not a good idea they do not hold humidity at all not what i decided to go with after all my searching was these http://www.ebay.com/itm/22-GALLON-DE...item20c52d4baa copy paste that into your web broser and it will come up with it on ebay they are very nice and best price you will find i promise i did the searching. I had three of these untill i just made my own nice rack system. Reason i went with these instead of the next option i im going to say in a minute is because i wanted to use heat pads to heat it from the bottom not heat bulbs which i felt was a better way after all my research then bulbs. And one of the best parts of these is they have a lip on the bottom to lift it of the ground so when you put the heat pads on it there is air flow under the tank and room for the wires ect. Only problem i had with these is there was no wire acces in it so i cut out a peice of the screen and mad my own desing worked well with some holes drilled in the back to run the wires and digital humidity gage ect. I still have one that im currently using as a very high priced feeder tank i would sell for 120 with two ultra therm 6 x11 inch under tank heater included shipped if you are interested. Or i would go with one of these tanks if you want to use ceramic bulb for heat which i personaully dont recommend. But if you do want to go that route this is my personaul choice for that option here is the link
http://www.visionproducts.us/htm7/cages.html again copy paste that in the search window to view the different size options on those tanks. If you are interested in seeing some pics of the one i have left i can be reached at 603-790-0029 cell thanks and hope you find what you are looking for. This size tank will be more then enough for a couple years if not longer depending on male or female, how well they eat for you, and how often you feed ect. Some would say good for life for a male not in my opinion thow. Hope this helps you out

Jeff